I setup a new email server in the same doamin yesterday. i tested it and it worked. then got home and mail.companyname.com didnt work so i changed the firewall to reflect the new mail server ip. tested and viola it worked. then an hour later everything failed. i couldnt figure it out why it worked then failed so maybe its dns. i checked dns and i have corp.mydomainname.com and a mydomainname.com. the active directory domain is corp. and mail is going to mydomainname.com. so i create an mx record and a ptr record to the mail.mycompany.com and to the internal ip for the ptr record. still nothing works. but i can still send email. nslookups fail so i know something isnt right. and i did a domain dns test and it says i do not have an mx recrod for my domain. so i got my isp to get an mx record but i doont know if that needs to go to mail.mydomain.com or to mydomain.com. Very confused and email is still down. any help is appreciated!!

If NSLOOKUP fails its DNS for sure. I imagine you've got DNS setup seperatly for AD and for public access, so make sure your MX record is correct on your authoratative internet facing DNS server.

yes there is an ldap server. but i have no access the last IT guy left and i haveno user id or pw and its a linux box so I would have a hard time anyways since i am more of a windows person. I am thinking to register my MX record with my ISP. Although my domain name is going through another provider. My isp is XO and my domain is registered at joker.com. i should be able to register with xo - i think. after i register i am lost as to what to do on my dns server. i think i still need to add mail.domain.com and point that to the external ip, right? and create an mx that goes to mail.domain.com, right? i think i have it setup ok with a zone for corp.domain.com and a zone for domain.com. atleast i hope so.

I got the MX record from my provider, its mail.westgatecap.com pointing to my mail server external IP of 208.36.254.98. I do an nslookup and now i can resolve mail. to 208. and vice versa. BUT I do an MX test online and I still get no MX found and when I do nslookup set q=mx it says non-exiting domain. any help would be great!! Monday and they want mail working! By the way I unplugged that DNS server since everything else is internal but Mail right now.

You unplugged your AD DNS server? That'll break a lot of exchange related stuff really soon! If your ISP just made the change, it takes time to propogate. otherwise it sounds like they might just have TCP 53 open and not UDP 53 to the dns server.

no i unplugged our ldap server its a ux box. i registered my mx record and mail just started coming thru today.